Light-emitting device

ABSTRACT

A light-emitting device comprises a light-emitting semiconductor stack comprising a plurality of recesses and a mesa, each of the plurality of recesses comprising a bottom surface, and the mesa comprising an upper surface; a first electrode formed on the upper surface of the mesa; a plurality of second electrodes respectively formed on the bottom surface of the plurality of recesses; a first electrode pad formed on the light-emitting semiconductor stack and contacting with the first electrode; a second electrode pad formed on the light-emitting semiconductor stack and contacting with the plurality of second electrode; a first insulating layer comprising a plurality of passages to expose the plurality of second electrodes; and a second insulating layer comprising a plurality of spaces and formed on the first insulating layer, wherein the plurality of spaces is covered by the first electrode pad.

REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 15/067,517, filed on Mar. 11, 2016, which is acontinuation application of U.S. patent application Ser. No. 14/150,418,filed on Jan. 8, 2014, now issued, which claims the right of prioritybased on TW application Serial No. 102101041, filed on Jan. 10, 2013,and the contents of which are hereby incorporated by references in theirentireties.

TECHNICAL FIELD

The present application relates to a light-emitting device and amanufacturing method of the same, and particularly to a light-emittingdevice comprising an electrode comprising a first layer and a secondlayer, and to a manufacturing method of the same.

DESCRIPTION OF BACKGROUND ART

Light-emitting diodes (LEDs) are widely used as light sources insemiconductor devices. Compared to conventional incandescent light lampsor fluorescent light tubes, light-emitting diodes have advantages suchas lower power consumption and longer lifetime, and therefore theygradually replace the conventional light sources and are applied tovarious fields such as traffic lights, back light modules, streetlighting, and medical equipment.

As the demand for the brightness of light-emitting diodes is gettinghigher as the applications and developments evolve, it is a common goalfor LED industry to make efforts to increase luminescence efficiency andbrightness.

FIG. 9 shows a conventional LED package 30 comprising an encapsulation31; a semiconductor LED chip 32 encapsulated in the encapsulation 31,wherein the semiconductor LED chip 32 comprises a p-n junction 33, andthe encapsulation 31 is usually made of thermosetting material, such asepoxy, or thermoplastic material.

The semiconductor LED chip 32 is connected to two conductive frames 35,36 by a wire 34. The epoxy-encapsulated LED can only work in a lowtemperature environment since degradation of epoxy can occur at hightemperature. Besides, epoxy has high thermal resistance, providing thesemiconductor LED chip 32, as shown in FIG. 9, a high resistance to heatdissipation, and thus the conventional LED package 300 is limited towork at low power levels.

SUMMARY OF THE DISCLOSURE

A light-emitting device comprises: a light-emitting semiconductor stackcomprising a recess and a mesa, wherein the recess comprises a bottom,and the mesa comprises an upper surface; a first insulating layer in therecess and on a part of the upper surface of the mesa; a first electrodecomprising a first layer and a second layer, wherein the first layercomprises a first conductive material and is on another part of theupper surface of the mesa, and the second layer comprises a secondconductive material and is on the first layer.

A light-emitting device comprises: a first electrode comprising a firstlayer and a second layer, wherein a first conductive material of thefirst layer is different from a second conductive material of the secondlayer, and a reflectivity of the first layer of the first electrode to alight generated by the light-emitting device is larger than areflectivity of the second layer of the first electrode to the light,and the reflectivity of the second layer is larger than 60%.

A light-emitting device comprises a light-emitting semiconductor stackcomprising a plurality of recesses and a mesa, each of the plurality ofrecesses comprising a bottom surface, and the mesa comprising an uppersurface; a first electrode formed on the upper surface of the mesa; aplurality of second electrodes respectively formed on the bottom surfaceof the plurality of recesses; a first electrode pad formed on thelight-emitting semiconductor stack and contacting with the firstelectrode; a second electrode pad formed on the light-emittingsemiconductor stack and contacting with the plurality of secondelectrode; a first insulating layer comprising a plurality of passagesto expose the plurality of second electrodes; and a second insulatinglayer comprising a plurality of spaces and formed on the firstinsulating layer, wherein the plurality of spaces is covered by thefirst electrode pad.

A light-emitting device comprises a light-emitting semiconductor stackcomprising a plurality of recesses and a mesa, each of the plurality ofrecesses comprising a bottom surface, and the mesa comprising an uppersurface; a first insulating layer formed in the plurality of recessesand on the upper surface of the mesa; a first electrode comprising afirst layer formed on the upper surface of the mesa and a second layerformed on the first layer; a plurality of second electrodes respectivelyformed on the bottom surface of the plurality of recesses; a secondinsulating layer formed on the second layer of the first electrode andcomprising one or multiple spaces exposing the second layer of the firstelectrode, wherein the first insulating layer comprises an openingexposing the first layer, the opening of the first insulating layercomprises a width larger than a width of the one or multiple spaces ofthe second insulating layer; a first electrode pad formed on thelight-emitting semiconductor stack and electrically connected to thefirst electrode; and a second electrode pad formed on the light-emittingsemiconductor stack and electrically connected to the plurality ofsecond electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 1B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 1A;

FIG. 2A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 2B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 2A;

FIG. 3A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 3B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 3A;

FIG. 3C is a cross-sectional diagram along the cross section line ofB-B′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 3A;

FIG. 4A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 4B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 4A;

FIG. 4C is a cross-sectional diagram along the cross section line ofB-B′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 4A;

FIG. 5A is a top view of a light-emitting device in accordance with thefirst embodiment during a manufacturing process of the presentapplication;

FIG. 5B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 5A;

FIG. 5C is a cross-sectional diagram along the cross section line ofB-B′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 5A;

FIG. 6A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 6B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 6A;

FIG. 6C is a cross-sectional diagram along the cross section lines ofB-B′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 6A;

FIG. 7A is a top view of a light-emitting device during a manufacturingprocess in accordance with the first embodiment of the presentapplication;

FIG. 7B is a cross-sectional diagram along the cross section line ofA-A′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 7A;

FIG. 7C is a cross-sectional diagram along the cross section line ofB-B′ in accordance with the light-emitting device during a manufacturingprocess of the present application shown in FIG. 7A;

FIG. 8 is a top view of a finished light-emitting device in accordancewith the first embodiment of the present application;

FIG. 9 illustrates a conventional LED package of a semiconductorlighting device; and

FIG. 10 is an exploded view of a light bulb in accordance with anotherembodiment of the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Exemplary embodiments of the present application will be described indetail with reference to the accompanying drawings hereafter. Thefollowing embodiments are given by way of illustration to help thoseskilled in the art fully understand the spirit of the presentapplication. Hence, it should be noted that the present application isnot limited to the embodiments herein and can be realized by variousforms. Further, the drawings are not precise scale and components may beexaggerated in view of width, height, length, etc. Herein, the similaror identical reference numerals will denote the similar or identicalcomponents throughout the drawings.

FIGS. 1A to 8 illustrate cross-sectional views of a light-emittingdevice during a manufacturing process in accordance with the firstembodiment of the present application.

FIG. 1A is a top view of a light-emitting device in accordance with oneof the embodiments of the present application. A light-emitting devicecomprises a substrate (not shown) and a light-emitting semiconductorstack comprising a first conductive type semiconductor layer 11, anactive layer (not shown) on the first conductive type semiconductorlayer 11, and a second conductive type semiconductor layer 12 on theactive layer. A part of the second conductive type semiconductor layer12 and a part of the active layer are etched to expose the firstconductive type semiconductor layer 11. FIG. 1B is a cross-sectionaldiagram along the cross section line of A-A′ in accordance with thelight-emitting device of the present application shown in FIG. 1A. Thelight-emitting device further comprises one recess 22 and a mesa 23, inthe present embodiment, the light-emitting device comprises a pluralityof recesses 22, wherein each recess 22 comprises a bottom and the mesa23 comprises an upper surface 231. In the present embodiment, the uppersurface 231 of the mesa 23 is a surface of the second conductive typesemiconductor layer 12. The bottom of each recess 22 exposes the firstconductive type semiconductor layer 11 and penetrates through the activelayer 21. After completing the light-emitting device, a voltage isapplied to the light-emitting device so as to enable the firstconductive type semiconductor layer 11 to provide electrons and enablethe second conductive type semiconductor layer 12 to provide holes, andthen light emits from the active layer 21 by the recombination ofelectrons and the holes. Referring to FIG. 2A and FIG. 2B, a secondelectrode 13 is formed at the bottom of each recess 22 and on the firstconductive type semiconductor layer 11, and the second electrode 13 iselectrically connected to the first conductive type semiconductor layer11.

Referring to FIG. 3A, the cross section areas along the cross sectionline of A-A′ and along the cross section line of B-B′ are different instructures and processes, and thus the two cross section areas aredescribed separately hereinafter.

Referring to FIG. 3B, a cross-sectional diagram along the cross sectionline of A-A′ shown in FIG. 3A, a first insulating layer 14 is formed ineach recess 22 and on a part of the upper surface 231 of the mesa 23,and the first insulating layer 14 covers the second electrode 13.

Referring to FIG. 4A and FIG. 4B, a first layer 15 of a first electrodeis then formed on another part of the upper surface 231 of the mesa 23,and the first layer 15 is spatially separated from the first insulatinglayer 14. Accordingly, the first insulating layer 14 is exposed. In thepresent embodiment, the first layer 15 of the first electrode comprisesa first conductive material comprising metal. Specifically, the firstconductive material comprises a material comprising an element selectedfrom the group consisting of Ag, Pt, and Au. The thickness of the firstlayer 15 of the first electrode ranges from 500 to 5000 Å. Referring toFIG. 5A and FIG. 5B, a second layer 16 of the first electrode is formedon the first layer 15, and the second layer 16 of the first electrodecovers the first layer 15 and at least a part of the first insulatinglayer 14, and thus the second layer 16 covers recesses 22. In thepresent embodiment, the second layer 16 of the first electrode comprisesa second conductive material comprising metal. Specifically, the secondconductive material comprises a material comprising an element selectedfrom the group consisting of Ni, Al, Cu, Cr, and Ti. The thickness ofthe second layer 16 of the first electrode ranges from 2000 Å to 1.5 μm.In another embodiment, the first conductive material of the first layer15 is different from the second conductive material of the second layer16. Furthermore, a reflectivity of the first layer 15 of the firstelectrode to a light generated by the light-emitting device is largerthan a reflectivity of the second layer 16 of the first electrode to thelight. Specifically, the reflectivity to the light of the second layeris larger than 60%.

Referring to FIG. 6A and FIG. 6B, a second insulating layer 17 is formedon the second layer 16 of the first electrode. Furthermore, a pluralityof spaces is formed by the second insulating layer 17 so as to expose anupper surface of the second layer 16 of the first electrode, wherein theplurality of spaces is separated from one another. Furthermore, thesecond insulating layer 17 is at a position corresponding to theposition of the first insulating layer 14. Specifically, the secondinsulating layer 17 is substantially right above the first insulatinglayer 14. In the present embodiment, a part of the second insulatinglayer 17 that is at the edge of the light-emitting device directlycontacts the first insulating layer 14. A material of the firstinsulating layer 14 can be the same as or different from a material ofthe second insulating layer 17. The materials of the first insulatinglayer 14 and the second insulating layer 17 can be silicon oxide,silicon nitride, aluminum oxide, zirconium oxide or titanium Oxide.Referring to FIG. 7A and FIG. 7B, a first electrode pad 18 is thenformed on the second insulating layer 17 and in the plurality of spaces.Furthermore, the first electrode pad 18 is electrically connected to thefirst layer 15 and the second layer 16 of the first electrode.

Referring to FIG. 3C, a cross-sectional diagram along the cross sectionline of B-B′ shown in FIG. 3A, the first insulating layer 14 is formedin each recess 22 and on a part of the upper surface 231 of the mesa 23.In the present embodiment, a part of an upper surface of the secondelectrode 13 is not covered by the first insulating layer 14, so as toform at least one passage 20 exposing the part of the upper surface ofthe second electrode 13. In the present embodiments, the light-emittingdevice comprises a plurality of passages. Referring to FIG. 4A and FIG.4C, the first layer 15 of the first electrode is on another part of theupper surface 231 of the mesa 23, and the first layer 15 is spatiallyseparated from the first insulating layer 14.

In the present embodiment, the first layer 15 of the first electrodecomprises the first conductive material comprising metal. Specifically,the first conductive material comprises a material comprising an elementselected from the group consisting of Ag, Pt, and Au. The thickness ofthe first layer 15 of the first electrode ranges from 500 to 5000 Å.Referring to FIG. 5A and FIG. 5C, the second layer 16 of the firstelectrode is formed on the first layer 15, and the second layer 16 ofthe first electrode covers the first layer 15 and at least a part of thefirst insulating layer 14. In the present embodiment, the second layer16 of the first electrode is at a position corresponding to the positionof the second conductive type semiconductor layer 12 so as to expose thepassages 20 exposing the part of the upper surface of the secondelectrode 13. The second layer 16 of the first electrode comprises thesecond conductive material comprising metal. Specifically, the secondconductive material comprises a material comprising an element selectedfrom the group consisting of Ni, Al, Cu, Cr, and Ti. The thickness ofthe second layer 16 of the first electrode ranges from 2000 Å to 1.5 μm.In another embodiment, the first conductive material of the first layer15 is different from the second conductive material of the second layer16. Furthermore, the reflectivity of the first layer 15 of the firstelectrode to the light generated by the light-emitting device is largerthan the reflectivity of the second layer 16 of the first electrode tothe light. Specifically, the reflectivity to the light of the secondlayer is larger than 60%.

Referring to FIG. 6A and FIG. 6C, the second insulating layer 17 isformed on the second layer 16 of the first electrode and on the firstinsulating layer 14. Specifically, the second insulating layer 17 doesnot cover the passages 20, and thus the part of the upper surface of thesecond electrode 13 is still exposed by the passages 20. Furthermore, apart of the second insulating layer 17 directly contacts the firstinsulating layer 14. A material of the first insulating layer 14 can bethe same as or different from a material of the second insulating layer17. The materials of the first insulating layer 14 and the secondinsulating layer 17 can be silicon oxide, silicon nitride, aluminumoxide, zirconium oxide or titanium Oxide. Referring to FIG. 7A and FIG.7C, a second electrode pad 19 is then formed on the second insulatinglayer 17 and in the passages 20. Specifically, the second electrode pad19 directly contacts the part of the upper surface of the secondelectrode 13 that is not covered by the first insulating layer 14.Furthermore, the second electrode pad 19 is electrically connected tothe second electrode 13. FIG. 8 is a top view of a finishedlight-emitting device 10 in accordance with the first embodiment of thepresent application.

FIG. 10 is an exploded view of a light bulb 40 in accordance withanother embodiment of the present application. The light bulb 40comprises a cover 41, a lens 42 disposed in the cover 41, a lightingmodule 44 disposed under the lens 42, a cover holder 45, a heat sink 46,a connecting part 47, and an electrical connector 48, wherein theconnecting part 47 connects the cover holder 45 to the electricalconnector 48. Furthermore, the lighting module 44 comprises a carrier 43and a plurality of light-emitting devices 10 of an embodiment asmentioned above, wherein the plurality of light-emitting devices 10 ison the carrier 43.

The materials of the second electrode 13, the first electrode pad 18 andthe second electrode pad 19 comprise metal such as Cr, Ti, Ni, Pt, Cu,Au, Al, W, Sn, or Ag. The substrate (not shown) is used for growingand/or a base carrier. The material of the substrate comprisestransparent material comprising sapphire, LiAlO₂, ZnO, GaN, AlN, glass,diamond, chemical vapor deposition diamond (CVD diamond), diamond-likecarbon (DLC), MgAl2O4 (spinel), silicon oxide (SiO_(x)), or LiGaO₂.

The first conductive type semiconductor layer 11 and the secondconductive type semiconductor layer 12 as mentioned above are differentin electricity, polarity or dopant, or are different in semiconductormaterials used for providing electrons or holes, wherein thesemiconductor materials can be a single semiconductor material layer ormultiple semiconductor material layers. As used herein, “multiple” isgenerally defined as two or more than two. The polarity can be chosenfrom any two of the group consisting of p-type, n-type and i-type. Theactive layer 21, where the electrical energy and the light energy can beconverted or stimulatively converted, is disposed between the firstconductive type semiconductor layer 11 and the second conductive typesemiconductor layer 12. Specifically, the active layer, where theelectrical energy is converted or the light energy is induced, can be alight-emitting diode, a liquid crystal display, or an organiclight-emitting diode, and the active layer, where the light energy isconverted or the electrical energy is induced, can be a solar cell or aphoto diode. The materials of the first conductive type semiconductorlayer 11, the active layer 21 and the second conductive typesemiconductor layer 12 comprise a material comprising an elementselected from the group consisting of: Ga, Al, In, As, P, N, Si, and thecombination thereof.

The emission spectrum of a light-emitting device of another embodimentin the present application can be adjusted by changing the physical orchemical factors of the single semiconductor material layer or themultiple semiconductor material layers. The material can be AlGaInPseries, AlGaInN series, or ZnO series. The structure of the active layer(not shown) can be single heterostructure (SH), double heterostructure(DH), double-side double heterostructure (DDH) or multi-quantum well(MQW), wherein the wavelength of the light emitted from the active layer(not shown) can be changed by adjusting the number of MQW pairs.

In one of the embodiments of the present application, a buffer layer(not shown) can be optionally disposed between the first conductive typecontact layer 11 and the substrate (not shown). The buffer layer isbetween two material systems so as to make a transition between thematerial system of the substrate and the material system of thesemiconductor layer. For the structure of the light-emitting device, thebuffer layer is used to reduce the lattice mismatch between two layerswith different materials. On the other hand, the buffer layer comprisesa single layer, multiple layers or a structure which comprises twomaterials or two separated structures. The material of the buffer layercan be organic material, inorganic material, metal or semiconductormaterial. The structure of the buffer layer can be a reflective layer, athermally conductive layer, an electrically conductive layer, an ohmiccontact layer, an anti-deformation layer, a stress release layer, abonding layer, a stress adjustment layer, a wavelength conversion layeror a mechanically fixing structure. In another embodiment, the materialof the buffer layer can be AlN or GaN, and the buffer layer can beformed by sputtering or atomic layer deposition (ALD).

A second conductive type contact layer (not shown) can be optionallyformed on the second conductive type semiconductor layer 12. The secondconductive type contact layer is disposed on a side of the secondconductive type semiconductor layer 12 away from the active layer 21.More specifically, the second conductive type contact layer can be anoptical layer, an electrical layer, or the combination thereof. Theoptical layer (not shown) can change the electromagnetic radiation orthe light from or entering the active layer 21. that is, the opticallayer can change at least one of the optical properties of theelectromagnetic radiation or the light, wherein the optical propertiescomprises frequency, wavelength, intensity, flux, efficiency, colortemperature, rendering index, light field and angle of view. Theelectrical layer can substantially change or slightly change at leastvalue, density or distribution of the voltage, resistance, current andcapacitance of any two opposite sides of the second conductive typecontact layer. The material of the second conductivity type contactlayer comprises oxide such as conductive oxide, transparent oxide andthe oxide with a transparency not less than 50%, or comprises metal suchas transparent metal and the metal with a transparency not less than50%, or comprises organic material, inorganic material, fluorescematerial, phosphor material, ceramic, undoped semiconductor material ordoped semiconductor material. In some aspects, the material of thesecond conductivity type contact layer can be indium tin oxide, cadmiumtin oxide, antimony tin oxide, indium zinc oxide, aluminum zinc oxide,or zinc tin oxide. If the material of the second conductivity typecontact layer is a transparent metal, the thickness of the secondconductivity type contact layer ranges from 0.005 μm to 0.6 μm.

The foregoing description of preferred and other embodiments in thepresent disclosure is not intended to limit or restrict the scope orapplicability of the inventive concepts conceived by the Applicant. Inexchange for disclosing the inventive concepts contained herein, theApplicant desires all patent rights afforded by the appended claims.Therefore, it is intended that the appended claims include allmodifications and alterations to the full extent that they come withinthe scope of the following claims or the equivalents thereof.

What is claimed is:
 1. A light-emitting device, comprising: a light-emitting semiconductor stack comprising a plurality of recesses and a mesa, each of the plurality of recesses comprising a bottom surface, and the mesa comprising an upper surface; a first insulating layer formed in the plurality of recesses and on the upper surface of the mesa; a first electrode comprising a first layer formed on the upper surface of the mesa and a second layer formed on the first layer; a plurality of second electrodes respectively formed on the bottom surface of the plurality of recesses; a second insulating layer formed on the second layer of the first electrode and comprising one or multiple spaces exposing the second layer of the first electrode, wherein the first insulating layer comprises an opening exposing the first layer, the opening of the first insulating layer comprises a width larger than a width of the one or multiple spaces of the second insulating layer; a first electrode pad formed on the light-emitting semiconductor stack and electrically connected to the first electrode; and a second electrode pad formed on the light-emitting semiconductor stack and electrically connected to the plurality of second electrodes.
 2. The light-emitting device according to claim 1, further comprising a substrate on the light-emitting semiconductor stack.
 3. The light-emitting device according to claim 1, wherein the light-emitting semiconductor stack comprises a first conductive type semiconductor layer, an active layer on the first conductive type semiconductor layer, and a second conductive type semiconductor layer on the active layer, the plurality of recesses penetrates through the active layer.
 4. The light-emitting device according to claim 3, wherein the bottom surface of the plurality of recesses exposes the first conductive type semiconductor layer, and the upper surface of the mesa is a surface of the second conductive type semiconductor layer.
 5. The light-emitting device according to claim 1, wherein the first electrode pad is formed on the plurality of recesses.
 6. The light-emitting device according to claim 1, wherein the first layer comprises a first conductive material and the second layer comprises a second conductive material different from the first conductive material.
 7. The light-emitting device according to claim 6, wherein the first conductive material comprises a material comprising an element selected from the group consisting of Ag, Pt, and Au, and the second conductive material comprises a material comprising an element selected from a group consisting of Ni, Al, Cu, Cr, and Ti.
 8. The light-emitting device according to claim 1, wherein the second insulating layer comprises a material different from that of the first insulating layer.
 9. The light-emitting device according to claim 8, wherein a material of the second insulating layer comprises silicon oxide, silicon nitride, aluminum oxide, zirconium oxide, or titanium oxide.
 10. The light-emitting device according to claim 1, wherein the second insulating layer is formed on the first insulating layer at a position overlapping a position of the first insulating layer.
 11. The light-emitting device according to claim 1, wherein the second insulating layer is between the first electrode and the first electrode pad.
 12. The light-emitting device according to claim 1, wherein the first electrode pad is formed on the second insulating layer and electrically connected to the first electrode through the one or multiple spaces.
 13. The light-emitting device according to claim 1, wherein the first insulating layer is formed in each of the plurality of recesses and on a part of the upper surface of the mesa.
 14. The light-emitting device according to claim 1, wherein the second insulating layer directly contacts the first insulating layer at an edge of the light-emitting device.
 15. The light-emitting device according to claim 1, wherein the first insulating layer comprising a plurality of passages to expose the plurality of second electrodes, the second insulating layer comprises a plurality of openings formed under the second electrode pad.
 16. The light-emitting device according to claim 15, wherein the second electrode pad is electrically connected to the plurality of second electrode through the plurality of openings of the second insulating layer and through the plurality of passages of the first insulating layer.
 17. The light-emitting device according to claim 1, further comprising a conductive type contact layer formed on the second conductive type semiconductor layer, wherein the conductive type contact layer comprises indium tin oxide, cadmium tin oxide, antimony tin oxide, indium zinc oxide, aluminum zinc oxide, or zinc tin oxide.
 18. The light-emitting device according to claim 1, wherein the multiple spaces are separated from each other. 